Applications of mammalian cells II Flashcards
What are vaccines?
- Biological preparations that provide active acquired immunity to a particular disease.
- Often made from weakened, inactivated or killed forms of microbes, toxins or one of its surface proteins
Describe virus production
- Not very different from antibody production
- The virus replicates inside the CELL and the cell environment is the ‘culture environment’
- ‘CULTURE WITHIN A CULTURE’
- Viruses can be produced in eggs (e.g. influenza) or in mammalian cell cultures
Describe vaccines production in embryonated eggs
- Eggs are the perfect natural mini-bioreactor (nutrient-rich, aseptic, do not contain other viruses that could contaminate the final product and are gas-permeable)
- Many viruses grow very well in embryonated chicken eggs
- Robust yield enables use for research and vaccine production
Vaccines production in embryonated eggs (2)
Animal cell culture for viral vaccine production
- FLUCELVAX (US) / Optaflu (EU) (Novartis) – first mammalian-cell based vaccine against the Influenza virus (2012) produced in MDCK cells.
- POLIO – in Vero cells or human diploid fibroblasts (HDF)
- RABIES – In Vero cells
- MEASLES, MUMPS – in chicken embryo cells
- RUBELLA, CHICKEN POX – in human diploid lung fibroblasts
Animal cell culture for viral vaccine production (2)
- Animal viruses propagated by cultured cells at relatively high density.
- Anchorage-dependent cell growth (e.g. Vero cells) particularly well suited for viral growth and for large-scale production, with microcarrier cultures often being used
Two phase process:
- Growth phase, where the objective is to increase mammalian cell biomass;
- Production phase, where the objective is to maximise the conversion of the mammalian cell biomass to viable viral biomass.
- The viral inoculation is accompanied by a feed in order to keep the cells alive and to maximise the virus production
Examples of viral vaccines: Describe the polio vaccine
- Polio (poliomyelitis or infantile paralysis)
- Caused by the poliovirus.
- Transmission by oral-faecal route.
- Multiplies in the throat and intestine.
- Invades the blood and lymph.
- Sub-clinical: mild symptoms in 95% of people.
- Clinical:
- non-paralytic polio
- paralytic polio – 1% of cases
How many deaths were from Polio in the 1949 epidemic?
In the 1949 epidemic, 2,720 deaths from the disease occurred in the United States and 42,173 cases were reported and Canada and the United Kingdom were also affected.
1954 - The Nobel Prize in Physiology or Medicine
(John F. Enders, Thomas H. Weller, Frederick C. Robbins) - “for their discovery of the ability of poliomyelitis viruses to grow in cultures of various types of tissue.”
Two types of Polio vaccines (Jonas Salk Polio vaccine) are used:
An inactivated poliovirus given by injection or
A weakened poliovirus given by mouth.
Describe the polio vaccine
- Developed and tested in 1952, released in 1955
- Cultured live Poliovirus in monkey kidney epithelial cells (Vero)
- Virus harvested and killed by formaldehyde
- Injected vaccine
provides IgG mediated immunity to prevent viremia;
60-90% protection.
- In 1957, Albert Sabin developed a live attenuated Polio vaccine by passaging Poliovirus through monkeys
oral vaccine that gives intestinal mucosal immunity;
occasionally mutates back and gives people Polio (1 in 750,000 doses).
Human tissue plasminogen activator (tPA)
- Activates plasmin which, in turn, digests fibrin to dissolve blood clots
- First recombinant protein produced by mammalian cell culture (CHO cells) to reach the market (1986)
- Activase® (Alteplase)
- Manufactured by Genentech
Give examples of therapeutic products, the cell type used in culture and the method of viral inactivation/ depletion
